On the subway system here in Boston, the ambient noise levels are very comparable to the level on an airplane, although it sounds very different.

在波士顿的铁路系统中，其环境噪音水平与飞行中的飞机不相上下，虽然它们听起来不大一样。

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Underwater acoustic channel is a time-space-frequency variant channel, having a character for narrow bandwidth, high ambient noise level and strong interference of multipath.

而由此构成的水声信道是一个空间与频率响应随机快速变化的传输信道，存在窄带、高噪及强多途干扰。

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The noise in the shell increases along with the level of ambient noise in the surrounding area.

贝壳中的声音会随着周围杂音的音量变大而增强。

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It would even apparently incorporate a noise meter that could automatically trigger various options when the ambient noise hits a certain level.

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